//  MeCab -- Yet Another Part-of-Speech and Morphological Analyzer
//
//
//  Copyright(C) 2001-2006 Taku Kudo <taku@chasen.org>
//  Copyright(C) 2004-2006 Nippon Telegraph and Telephone Corporation
#ifndef MECAB_LBFGS_H_
#define MECAB_LBFGS_H_

#include <vector>
#include <iostream>

namespace SCRF {

class LBFGS {
public:
	explicit LBFGS() :
			iflag_(0), iscn(0), nfev(0), iycn(0), point(0), npt(0), iter(0), info(
					0), ispt(0), isyt(0), iypt(0), maxfev(0), stp(0.0), stp1(
					0.0), mcsrch_(0) {
	}
	virtual ~LBFGS() {
		clear();
	}

	void clear();

	int optimize(size_t size, double *x, double f, double *g, bool orthant,
			double C) {
		static const int msize = 5;
		if (w_.empty()) {
			iflag_ = 0;
			w_.resize(size * (2 * msize + 1) + 2 * msize);
			diag_.resize(size);
		} else if (diag_.size() != size) {
			std::cerr << "size of array is different" << std::endl;
			return -1;
		}

		lbfgs_optimize(static_cast<int>(size), msize, x, f, g, &diag_[0],
				&w_[0], orthant, C, &iflag_);

		if (iflag_ < 0) {
			std::cerr << "routine stops with unexpected error" << std::endl;
			return -1;
		}

		if (iflag_ == 0) {
			clear();
			return 0;   // terminate
		}

		return 1;   // evaluate next f and g
	}

private:
	class Mcsrch;
	int iflag_, iscn, nfev, iycn, point, npt;
	int iter, info, ispt, isyt, iypt, maxfev;
	double stp, stp1;
	std::vector<double> diag_;
	std::vector<double> w_;
	Mcsrch *mcsrch_;

	void lbfgs_optimize(int size, int msize, double *x, double f,
			const double *g, double *diag, double *w, bool orthant, double C,
			int *iflag);
};
}

#endif
